Method for producing a semiconductor storage device

ABSTRACT

In order to control the transmitting power provided for point-to-multipoint telecommunications links in a telecommunications system with wireless telecommunication and uncoordinated unlicensed system operation, without significant restriction of the transmitting range, use is made of the fact that the maximum number of mobile stations (MS1 . . . MSn) registered in a base station (BS1) is known. Thus, the base station knows at any time how many and which mobile stations are registered. If all mobile stations are registered (N ACT =N SCHED ), the base station can match the transmitting power to the mobile station received as the “weakest one”. In other cases, if not all mobile stations are registered (N ACT ≠N SCHED ), the base station will alternately transmit with the maximum transmitting. power for a predetermined first period of time and then with the reduced transmitting power, which matches the mobile station received as the “weakest one”, for a predetermined second period of time.

BACKGROUND OF THE INVENTION

Telecommunications systems with wireless telecommunications betweenmobile and/or stationary transceivers are special communication systemswith a message transmission path between a message source and a messagesink in which, for example, base stations and mobile parts are used astransceivers for message processing and transmission and in which

1) the message processing and message transmission can take place in onepreferred direction of transmission (simplex mode) or in both directionsof transmission (duplex mode),

2) the message processing is preferably digital,

3) the message transmission takes place wirelessly via the long-distancetransmission link on the basis of various message transmission methodsfor multiple utilization of the message transmission link FDMA(Frequency Division Multiple Access), TDMA (Time Division MultipleAccess) and/or CDMA (Code Division Multiple Access)—e.g. according toradio standards such as DECT [Digital Enhanced (previously: European)Cordless Telecommunications; compare Nachrichtentechnik Elektronik 42(1992) January/February No. 1, Berlin, DE; U. Pilger “Struktur desDECT-Standards” [Structure of the DECT standard], pages 23 to 29 inconjunction with ETSI Publication ETS 300175-1 . . . 9, October 1992 andthe DECT Publication of the DECT Forum, February 1997, pages 1 to 16],GSM [Groupe Speciale Mobile or Global System for Mobile Communication;compare Informatik Spektrum 14 (1991) June, No. 3, Berlin, DE; A. Mann:“Der GSM—Standard—Grundlage für digitale europäische digital Europeanmobile radio networks], pages 137 to 152 in conjunction with thepublication telekom praxis April 1993, P. Smolka“GSM-Funkschnittstelle—Elemente und Funktionen”, [GSM RadioInterface—Elements and Functions], pages 17 to 24], UMTS [UniversalMobile Telecommunications System; compare (1): NachrichtentechnikElektronik, Berlin 45, 1995, vol. 1, pages 10 to 14 and vol. 2, pages 24to 27; P. Jung, B. Steiner: “Konzept eines CDMA-Mobilfunksystems mitgemeinsamer Detektion für die dritte Mobilfunkgeneration” [Concept of aCDMA mobile radio system with joint detection for the third mobile radiogeneration]; (2): Nachrichtentechnik Elektronik, Berlin 41, 1991, vol.6, pages 223 to 227 and page 234; P. W Baier, P. Jung, A. Klein:“CDMA—ein günstiges Vielfachzugriffsverfahren für frequenzselektive undzeitvariante Mobilfunkkanäle” [CDMA—a favorable multiple access methodfor frequency-selective and time-variant mobile radio channels]; (3):IEICE Transactions on Fundamentals of Electronics, Communications andComputer Sciences, Vol. E79-A, No. 12, December 1996, pages 1930 to1937; P. W. Baier, P. Jung: “CDMA Myths and Realities Revisited”; (4):IEEE Personal Communications, February 1995, pages 38 to 47; A. Urie, MStreeton, C Mourot: “An Advanced TDMA Mobile Access System for UMTS”;(5): telekom praxis, May 1995, pages 9 to 14; P. W. Baier:“Spread-Spectrum-Technik und CDMA—eine ursprüglich militärische Technikerobert den zivilen Bereich” [Spread Spectrum Technology and CDMA—atechnology of military origin conquers the civil domain]; (6): IEEEPersonal Communications, February 1995, pages 48 to 53; P. G. Andermo,L. M. Ewerbring: “An CDMA-Based Radio Access Design for UMTS”; (7): ITGPachberichte 124 (1993), Berlin, Offenbach: VDE Verlag ISBN3-8007-1965-7, pages 67 to 75; Dr. T. Zimmermann, Siemens AG: “Anwendungvon CDMA in der Mobilkommunikation” [Applying CDMA in mobilecommunications]; (8): telecom report 16, (1993), vol. 1, pages 38 to 41;Dr. T. Ketseoglou, Siemens AG and Dr. T. Zimmermann, Siemens AG:“Effizienter Teilnehmerzugriff für die 3. Generation derMobilkommunikation—Vielfachzugriffsverfahren CDMA machtLuftschnittstelle flexibler” [efficient subscriber access for the 3rdgeneration of mobile communications—the multiple access method CDMAmakes the air interface more flexible]; (9): Funkschau June 1998: R.Sietmann “Ringen um die UMTS-Schnittstelle” [The struggling for the UMTSinterface], pages 76 to 81] WACS or PACS, IS-54, IS-95, PHS, PDC etc.[compare IEEE Communications Magazine, January 1995, pages 50 to 57; D.D. Falconer et al: “Time Division Multiple Access Methods for WirelessPersonal Communications”].

“Message” is a generic term which stands both for the meaning(information) and for the physical representation (signal). Even if amessage has the same meaning—i.e. the same information—different signalforms can occur. Thus, for example, a message concerning an object canbe transmitted

(1) in the form of an image,

(2) as spoken word,

(3) as written word,

(4) as encrypted word or image.

The type of transmission according to (1) . . . (3) is here normallycharacterized by continuous (analog) signals, whereas the type oftransmission according to (4) normally produces discontinuous signals(e.g. pulses, digital signals).

It is of great importance to carry out a power control for thetelecommunications systems specified above, and especially for theCDMA-based telecommunications systems, because of the “near-far”(compare: (10) K. D. Kammeyer “Nachrichtenübertragung” [MessageTransmission], B. G. Teubner Stuttgart 1996, chapter 16.1.3, especiallypage 636; (11) K. David/T. Benkner “Digitale Mobilfunksysteme” [DigitalMobile Radio Systems], B. G. Teubner Stuttgart 1996, chapter 8.7.2.2,especially page 414).

Power control is known as a means for reducing interference inmulticellular mobile radio networks. The basic idea is to allocate toeach subscriber only the amount of transmitting power currently neededby him for achieving the desired quality of service. This measureclearly reduces the interference with respect to other subscribers inthe same or adjacent cells. However, this technique can only be appliedto so-called “point-to-point” connections in cellular mobile radiosince, in this case, the transmitting powers to be used for thetransmission, e.g. between stationary and mobile transceivers, that isfrom a base station or fixed part to the mobile station or mobile partand vice versa, can be explicitly dedicated to the link between the basestation and mobile station.

In mobile radio telecommunications systems (e.g. GSM, UMTS) whichoperate preferably in licensed coordinated system operation, and incordless telecommunications systems (e.g. DECT, PHS etc.) whichpreferably operate in unlicensed uncoordinated system operation,however, point-to-multipoint connections are also used. Channels usingsuch links are generally Control Channels, the so-called “Common ControlChannels (CCCH)”. The most important representative of this category is,without any doubt, the so-called “Broadcast Control Channel (BCCH)”. Itis radiated in the down link (DL) by the base station. The broadcastcontrol channel has the task of transporting cell-related informationand synchronization information. These information items are used by allmobile stations located within the cell. Since, however, the positionsof the mobile stations within the radio cell and thus also thetransmitting powers needed can differ greatly, it is not possible tocontrol the transmitting power of the broadcast control channel incellular mobile radio. As a rule, the transmitting power of thebroadcast control channel is adapted in such a manner that it can stillbe received with adequate power by all mobile stations at the edge ofthe cell.

Power control is not used either for the “traffic channel (TCH)” or forthe “broadcast control channel” in the previous cordlesstelecommunications systems (e.g. DECT).

SUMMARY OF THE INVENTION

The object forming the basis of the invention consists in controllingthe transmitting power provided for point-to-multipointtelecommunications links in a telecommunications system with wirelesstelecommunications and uncoordinated unlicensed systemoperation—especially in a universal mobile telecommunications systemwith uncoordinated unlicensed system operation and a coordinatedlicensed system operation, without significant restriction of thetransmitting range.

This object is achieved by a method for controlling power inpoint-to-multipoint telecommunications links in telecommunicationssystems with wireless telecommunications and uncoordinated unlicensedsystem operation, comprising the following features: (a) a SCHEDULEDnumber of mobile parts registered in the base station is allocated tothe coverage area of a base station supporting uncoordinated unlicensedsystem operation, (b) the base station sends a first message to themobile parts located within the coverage area of the base station at apredetermined first time recurring at regular intervals in connectionwith a point-to-multipoint telecommunications link, (c) the respectivemobile part sends a second message to the base station in each case at amobile-part-specific second time recurring at regular intervals, thesecond time being determinable by events, such as especially the entryof the mobile part into the coverage area, the exit of the mobile partfrom the coverage area and/or the request for setting up apoint-to-point telecommunications link by the mobile part, (d) the basestation detects, by means of the second messages sent by the mobileparts, an ACTUAL number of mobile parts registered in the base stationand located within the coverage area of the base station, (e) if theACTUAL number matches the SCHEDULED number, the base station sends thefirst message with a first transmitting power which is reduced comparedwith a maximum power and which is dimensioned in such a manner that amobile part, the second message of which has been received as theweakest one in the base station, still reliably receives the firstmessage, (f) if the ACTUAL number does not match the SCHEDULED number,the base station alternately sends the first message with the maximumtransmitting power for a predetermined first period of time and thenwith the first transmitting power for a predetermined second period oftime.

The concept, proposed above, for the power control ofpoint-to-multipoint telecommunications links—especially of the broadcastcontrol channel—for telecommunications systems with wirelesstelecommunications and uncoordinated unlicensed systemoperation—especially future cordless telecommunications systems such as“residential UMTS” systems—makes use of the fact that the maximum numberof mobile stations registered in a base station is known. Thus, the basestation knows at any time how many and which mobile stations areregistered. If all mobile stations are registered—i.e. if a SCHEDULEDnumber of mobile stations registered in the base station corresponds toan ACTUAL number of mobile stations registered in the base station(N_(ACT)=N_(SCHED))—, the base station can match the transmitting power(first transmitting power) to the mobile station received as the“weakest one”. In other cases, if not all mobile stations areregistered—i.e. if the SCHEDULED number of mobile stations registered inthe base station does not correspond to the ACTUAL number of mobilestations registered in the base station (N_(ACT)≠N_(SCHED))—, the basestation will alternately transmit with the maximum transmitting powerfor a predetermined first period of time and then with the reducedtransmitting power, which matches the mobile station received as the“weakest one”, for a predetermined second period of time. This providesfor an optimum (dynamic) matching of the transmitting power to thecontinuously varying number of mobile stations located within thecoverage area of the base station.

This procedure described above is possible because, as a rule, onemobile station will be operated for each base station and this is alsoregistered, as a rule, in cordless telecommunications systems. Thetransmitting power selected by the base station in the first-mentionedcase (all mobile stations are registered) will essentially be reducedcompared with the maximum transmitting power (in the clearly predominantnumber of cases). The power-controlled point-to-multipointtelecommunications link minimizes the interference with other cordlesstelecommunications systems and thus improves the capability ofcoexistence. The method described above is suitable both forTDMA/FDMA-based systems and for CDMA-based systems. Power control isessential especially for CDMA-based systems since this makes it possibleto considerably reduce the “near-far” problem.

According to a preferred embodiment, it is advantageous if the secondperiod of time, according to a limit value consideration for periods oftime, on the assumption, which is generally valid for this, that aperiod of time can have a positive value between “zero” and—viewedtheoretically—“arbitrary or infinite”, has the value “zero”, that is tosay the base station only transmits with maximum transmitting power ifthe ACTUAL number does not match the SCHEDULED number, the base stationalternately sends the first message with the maximum transmitting powerfor a predetermined first period of time and then with the firsttransmitting power for a predetermined second period of time.

Additional advantageous further developments of the invention areprovided in that the point-to-multipoint telecommunications link is usedfor a broadcast control channel. The wireless telecommunications iscarried out in accordance with the CDMA, FDMA, and/or TDMA access methodand in accordance with the TDD and/or FDD principle.

BRIEF DESCRIPTION OF THE DRAWINGS

An exemplary embodiment of the invention is explained with reference toFIGS. 1 and 2, in which:

FIG. 1 shows a possible UMTS scenario with the section from a universalmobile telecommunications network and a universal mobiletelecommunications system operating both in uncoordinated unlicensedsystem operation and in coordinated licensed system operation,

FIG. 2 shows a message flowchart for the power-controlled transmissionof messages in point-to-multipoint telecommunications links.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a possible UMTS (Universal Mobile TelecommunicationsSystem) scenario comprising a multicellular universal mobiletelecommunications system UMTS operating both in uncoordinatedunlicensed system operation and in coordinated licensed systemoperation. The UMTS system shown exhibits a first telecommunicationssubsystem TKTS1, acting in first radio cells FZ1, with wirelesstelecommunications between a first base station BS1 and with n (nεN)first mobile stations MS1 . . . MSn, which operates in uncoordinatedunlicensed system operation. Moreover, the UMTS system exhibits a secondtelecommunications subsystem TKST2, acting in second radio cells FZ2,with wireless telecommunications between a second base station BS2 andwith m (mεN) second mobile stations MSn+1 . . . MSn+m, which operates incoordinated licensed system operation.

FIG. 2 shows a message flowchart with 13 diagram states occurringsuccessively in time for the power-controlled transmission of firstmessages N1 in point-to-multipoint telecommunications links by the firstbase station BS1 to the mobile stations MS1 . . . MSn. In the messageflowchart shown, it is assumed that the mobile stations MS1 . . . MSnspecifying a SCHEDULED number N_(SCHED) are registered in the first basestation BS1.

In a first diagram state DZ1, the base station BS1 sends the firstmessage 1 with a maximum transmitting power Pmax on the broadcastcontrol channel BCCH to the mobile stations MS1 . . . MSn at a firsttime T1.

In a second diagram state DZ2, the mobile stations MS1 . . . MSn send asecond message N2 to the base station BS1 at a second time T2. Themobile stations MS1 . . . MSn sending this second message N2 arecombined by means of an ACTUAL number N_(ACT).

In a third diagram state DZ3, the base station BS1 determines that theACTUAL number N_(ACT) and the SCHEDULED number N_(SCHED) are equal.

In a fourth diagram state DZ4, the base station BS1 sends the firstmessage N1 with a first transmitting power P1, which is reduced comparedwith the maximum transmitting power Pmax, in the broadcast controlchannel BCCH to the mobile stations MS1 . . . MSn at the first time T1.The first transmitting power P1 is dimensioned in such a manner that amobile part MS1 . . . MSn, the second message N2 of which has beenreceived as the weakest by the base station BS1, still receives thefirst message N1 reliably.

In a fifth diagram state DZ5, the mobile stations MS1, MS2 send thesecond message N2 to the base station BS1 at the second time T2. Themobile stations MS1 . . . MSn sending this second message N2 arecombined in the ACTUAL number N_(ACT).

In a sixth diagram state DZ6, the base station BS1 determines that theACTUAL number N_(ACT) and the SCHEDULED number N_(SCHED) are unequal.

In a seventh diagram state DZ7, the base station BS1 sends the firstmessage N1 with the maximum transmitting power Pmax in the broadcastcontrol channel BCCH to the mobile stations MS1 . . . MSn at the firsttime T1. Sending of the first message N1 with the maximum transmittingpower Pmax in the broadcast control channel BCCH to the mobile stationsMS1 . . . MSn at the first time T1 also takes place in an eighth diagramstate DZ8. The period of time which has elapsed from the seventh diagramstate DZ7, via the eighth diagram state DZ8, to a ninth diagram stateDZ9 is specified by a first period of time ΔT1 ₁.

After this first period of time ΔT₁, has elapsed, the first message N1is sent with the first transmitting power P1 in the broadcast controlchannel BCCH to the mobile stations MS1 . . . MSn from the base stationBS1 at the first time T1. Sending the first message N1 with the firsttransmitting power P1 in the broadcast control channel BCCH to themobile stations MS1 . . . MSn at the first time T1 also takes place in atenth diagram state DZ10. The period of time which has elapsed from theninth diagram state DZ9, via the tenth diagram state DZ10, to athirteenth diagram state DZ13 is specified by means of a second periodof time ΔT1 ₂.

In the period from the sixth diagram state DZ6 to this tenth diagramstate DZ10, it is assumed that the ACTUAL number N_(ACT) and theSCHEDULED number N_(SCHED) remains unchanged, that is to say unequal. Ifthis is not the case, the sequence is preferably immediately continuedin the same manner as described in the fourth diagram state DZ4. As analternative, it is also possible to allow the corresponding period ΔT1₁, ΔT1 ₂ to run its complete course and not to abort.

In an eleventh diagram state DZ11, the mobile stations MS1 . . . MSnsend the second message N2 to the base station BS1 at the second timeT2. The mobile stations MS1 . . . MSn sending this second message N2 areagain combined in the ACTUAL number N_(ACT).

In a twelfth diagram state DZ12, the base station BS1 determines thatthe ACTUAL number N_(ACT) and the SCHEDULED number N_(SCHED) are againequal.

In the thirteenth diagram state DZ13, the base station BS1 sends thefirst message N1 with the first transmitting power P1 in the broadcastcontrol channel BCCH to the mobile stations MS1 . . . MSn at the firsttime T1—as in the fourth diagram state DZ4.

The diagram states now following have been dealt with by the 13 diagramstates described above.

Although other modifications and changes may be suggested by thoseskilled in the art, it is the intention of the inventors to embodywithin the patent warranted hereon all changes and modifications asreasonably and properly come within the scope of their contribution tothe art.

We claim:
 1. A method for controlling power in point-to-multipointtelecommunications links in telecommunications systems with wirelesstelecommunications and uncoordinated unlicensed system operation,comprising the following features: (a) allocating a SCHEDULED number ofmobile parts registered in the base station to a coverage area of a basestation supporting uncoordinated unlicensed system operation, (b)sending a first message to the mobile parts located within the coveragearea of the base station at a predetermined first time recurring atregular intervals in connection with a point-to-multipointtelecommunications link by the base station, (c) sending a secondmessage to the base station in each case at a mobile-part-specificsecond time recurring at regular intervals by the respective mobilepart, the second time being determinable by events, (d) detecting anACTUAL number of mobile parts registered in the base station and locatedwithin the coverage area of the base station by the base station usingsecond messages sent by the mobile part, (e) if the ACTUAL numbermatches the SCHEDULED number, sending by the base station the firstmessage with a first transmitting power which is reduced compared with amaximum power and which is dimensioned in such a manner that a mobilepart, the second message of which has been received as the weakest onein the base station, still reliably receives the first message, (f) ifthe ACTUAL number does not match the SCHEDULED number, sending by thebase station the first message with the maximum transmitting power for apredetermined first period of time and then with the first transmittingpower for a predetermined second period of time.
 2. The method asclaimed in claim 1, wherein a period value “zero” is allocated to thesecond period of time.
 3. The method as claimed in claim 1, furthercomprising the step of: using a point-to-multipoint telecommunicationslink for a broadcast control channel.
 4. The method as claimed in claim1, wherein wireless telecommunications is carried out in accordance withone of CDMA, FDMA, and TDMA access method and in accordance with one ofTDD and FDD principle.